The water lines around the base of the structures are very telling... could indicate periodic releases of water from the domes, probably does... perhaps old leaks that stopped? Or an apparatus like a sprinkler on a timer that keeps the planet at just the right point of uninhabitability that can be recovered by the system?

I'm convinced of the authenticity of these being artificial structures as certain as I can be convinced of something that I cannot experience directly myself, the only question for me is whether we are seeing unintentionally defunct technology or something that lies in a dormant or semi-active state awaiting an activation.

Right now, if I had to go out on a limb, I think we are either seeing the last failed attempts of the prior inhabitants of Mars to keep the planet in a balance of sustainability or some system that has been placed their by entities from out of the solar system for us or them to activate at some point to make Mars habitable (again).